Teaching Model Integrating Online and Offline in Real Time ——An Exploration of New Teaching Mode for Regular Epidemic Prevention and Control

During epidemic,students in medium-risk or high-risk areas are unable to return to school on time.In response to this new challenge,there is an urgent need to create a new teaching mode to offer on-line courses to those absent from the offline classes,and we propose a model integrating online and offline teaching.It is based on“dual-camera”method,which allows off-campus students to virtually build up a physical classroom scenario on campus through computers and mobile phones.Using this model,students can participate in class remotely.In order to enhance the engagement of off-campus online students,emphasis is placed on interactive teaching.Teachers are required to design their teaching in advance and to work in collaboration with multiple departments,then using information technology and suitable teaching methods to enable students to participate in physical classroom teaching.This model has been tested in practice and has been successful in meeting the challenges.Finally,4 areas for improvement and refinement are identified.

Enhancing sensitivity to ambient refractive index with tunable few-layer graphene/hBN nanoribbons

Refractive index (RI) sensing helps to identify biomolecules and chemicals in the mid-infrared range for drug discovery, bioengineering, and environmental monitoring. In this paper, we numerically demonstrate an electrically tunable RI sensor with ultrahigh sensitivity using a three-layer graphene nanoribbon array separated by hexagonal boron nitride (hBN). Unlike the weak resonance in single-layer graphene nanoribbons, a much stronger plasmon resonance featuring a higher-quality factor can be excited in the graphene/hBN few-layer ribbon array. Simultaneously, the high purity of graphene on hBN results in an outstanding charge mobility above 4 ×10^4 cm^2 · V^-1·s^-1 at 300 K, which allows a larger modulation depth. The interaction between the locally enhanced field around graphene ribbons and its surrounding analyte leads to ultrahigh sensitivity (4.207μm/RIU), with the figure of merit reaching approximately 58.Moreover, this ultrasensitive detector could selectively work in different wavebands by controlling gate voltages applied to graphene.These merits of ultrahigh sensitivity and electrical tunability are major advances compared to previous RI sensors, paving a way toward ultrasensitive detection using graphene/hBN few-layer devices.

Unselective ground-state blockade of Rydberg atoms for implementing quantum gates

A dynamics regime of Rydberg atoms,unselective ground-state blockade(UGSB),is proposed in the context of Rydberg antiblockade(RAB),where the evolution of two atoms is suppressed when they populate in an identical ground state.UGSB is used to implement a SWAP gate in one step without individual addressing of atoms.Aiming at circumventing common issues in RAB-based gates including atomic decay,Doppler dephasing,and fluctuations in the interatomic coupling strength,we modify the RAB condition to achieve a dynamical SWAP gate whose robustness is much greater than that of the nonadiabatic holonomic one in the conventional RAB regime.In addition,on the basis of the proposed SWAP gates,we further investigate the implementation of a three-atom Fredkin gate by combining Rydberg blockade and RAB.The present work may facilitate to implement the RAB-based gates of strongly coupled atoms in experiment.

One-step implementation of Rydberg-antiblockade SWAP and controlled-SWAP gates with modified robustness

The prevalent fashion of executing Rydberg-mediated two-and multi-qubit quantum gates in neutral atomic systems is to pump Rydberg excitations using multistep piecewise pulses in the Rydberg blockade regime.Here, we propose to synthesize a Λ-type Rydberg antiblockade(RAB) of two neutral atoms using periodic fields,which facilitates one-step implementations of SWAP and controlled-SWAP(CSWAP) gates with the same gate time. Besides, the RAB condition is modified so as to circumvent the sensitivity of RAB-based gates to infidelity factors, including atomic decay, motional dephasing, and interatomic distance deviation. Our work makes up the absence of one-step schemes of Rydberg-mediated SWAP and CSWAP gates and may pave a way to enhance the robustness of RAB-based gates.

Unidirectional acoustic metamaterials based on nonadiabatic holonomic quantum transformations

Nonadiabatic holonomic quantum transformations(NHQTs)have attracted wide attention and have been applied in many aspects of quantum computation,whereas related research is usually limited to the field of quantum physics.Here we bring NHQTs into constructing a unidirectional acoustic metamaterial(UDAM)for shaping classical beams.The UDAM is made up of an array of three-waveguide couplers,where the propagation of acoustic waves mimics the evolution of NHQTs.The excellent agreement among analytical predictions,numerical simulations,and experimental measurements confirms the great applicability of NHQTs in acoustic metamaterial engineering.The present work extends research on NHQTs from quantum physics to the field of classical waves for designing metamaterials with simple structures and may pave a new way to design UDAMs that would be of potential applications in acoustic isolation,communication,and stealth.